Method of deflocculating solid materials.



'5. G. ACHESON.

MD.. R LL T.. AMA?. m DI L- 0U s. GM Nl' ,HD AE LL UH CN M0 LU r-IA EcDvu P F 0M D 0 H .l E M u. QN.. u

E'. G. ACHESON. MAETHQD 0F DEFLOCGULATING sono MATERqALs.

APPLICATION FILED IAN. 11| 1917.

' Patented Apr. 24, 1917 2 SHEETS-SHEET 2.

51H0: ne

EDWARD UNITED srn'rns PATEN'r .gornion To all whom z't mag/concern.' YBe it known that I, EDWARD GooDRIoH AC1-nasen, a citizen of the UnitedStates, re-

siding at New York, in the county of New York, and State of New York,have invented certain new and useful Improvements in Methods ofDeocculating Solid Materials, of which the following is a specification.

This invention relates to methods of deflocculating solid materials,such as graphite, lampblack, amorphous pigments or the like. It is nowwell understood in the art that such materials, when rubbed, ound, orsubjected to a process of attrition 1n presence of so-calleddelocculating agents are ultimately reduced to a state of extremesubdivision, as a result of which a -greater or less proportion of theparticles become permanently suspensible in water and capable ofdiffusing therethrough, and may by appropriate treatment be transferredto and suspended in vehicles other than water, for 'example mineraloils, etc. The delocculating agents above referred to comprise tanninand tannin-like substances, and other organic bodies or products havingsimilar effects. Certain methods of deiiocculating amorphous bodies andutilizing the deiocculated product are disclosed in my prior UnitedStates Patents Nos. 7 22,7 91; 843,426; 844,989; 875,881; 895,068;911,858; 981,882; 964,478; 966,686; 986,798; 1,080,872; 1,082,386;1,201,994. i

According to the present invention, the deocculation of amorphous bodiesis accomplished by a novel method, the essential fea.- ture of saidmethod being that the amorphous substance, mixed with the deflocculatingagent or an aqueous solution thereof, is subjectedV to a number ofdistinct and separate rubbing operations during which the particles ofthe mass are subjected to attrif' tion, with'intermediate periods whichmay be defined as periods of relative rest, in the sense that duringsuch intermediate periods the individual particles of the charge are notsubjected to an active or intensive attrition or rubbing. Y

The invention may be carried out in apparatus of various types, and maybe operated either according to the so-called batch system, orcontinuously or semi-continuously in the sense that the charge isintroduced into the mill and is discharged'therefrom either continuouslyor from time to time.

GooDRIcH AcnEsoN, or NEW- Yonxjmyanssenon Tomlinson couronne rIoN, orNEW YORK, N. kY., AconronATIoN oF DELAWARE. Y

nin'rnon or DEFLoocuLn'rINe s011113` MATERIALS;

Patented lAnwalt24, i'.

Application nled January 17, 1917. Serial No. 142,361.

Certain types of apparatus which may be used for carrying the inventioninto effec-t are diagrammatically illustrated in the accompanyingdrawings.

Referring to said drawings,-

Figure l represents in vertical section a simple form of mill capable ofbeing operated in accordance with the invention;

F ig. 2 is a similar view of a modified form of mill capable ofcontinuous operation; and

Fig. 3 is a similar view of a further modification, the mill being ofthe vertical type capable of continuous operation.

Referring to Fig. 1, 1 represents a driven roll, which may be` of ironor steel covered externally with canvas or other suitable fabric 2.`This roll'is mounted parallel to but out of actual contact with the baseplate 3, a suitable clearance', (sayonesixteenth` to oneeighth inch orsomewhat more) being provided between the roll and the plate. The rollis preferably mounted in a hopper-like receptacle indicated at 4, iscarried upon a shaft extending through the end Walls of the hopper, andis arranged to be driven by application of any suitable power atmoderate speeds, say ten to sixty revolutions per minute. The roll andits mounting should be sufficiently rigid to withstand the heavypressures involved in the operation. In practice the graphite or othermaterial to be deflocculated is mixed with the proper proportion of thedeiocculating agent in aqueous or ammoniacal solution, the mixtureforming a stiff paste of the character disclosed in my priorpatentsabove referred to."

In the case ofgraphite a suitable paste Will contain approximately 34 to38 per cent. of total moisture. rIhis paste, indicated at 6, is chargedinto the hopper at Aone side of the roll, and by the revolution of thelatter in the proper direction' is transferred beneath the roll to theother side of theV hopper. After a suitable time interval the directionIof rotation of the roll is reversed, and the material is againtransferred beneath the same, this operation being repeated as often asmay be required to secure the desired degree or percentage ofdeliocculation. For example, it was found in one specific instance thatpassages of the charge beneath the roll, a four-minute interval beingpermitted between the completion of one passage a-nd the beginning ofthe next, suced to deflocculate approximately ve per cent.

of the graphite-in the charge. lThe deocculated material may if 4desiredbe removed in` aqueous suspension, and the residue retreated, as fullyexplained in the prior patents above mentioned; o`r for certain aplications such separation may be omit A rolls-being preferably somounted as to pro- 20 vide a sli ht clearance from the lowerplate 9 butawiping contact with the upper plate 8. 10 represents the charginghopper. -The rolls driven bysuitable gearing (not shown) in thedirection indicated by the arrows, subject the charge to a series ofrubbings orperiods of intense attrition, alternating with periods ofrelative rest during which the charge remains between the rolls. Byvadthe spacing between the rolls the justiong peri -of relative rest mayof course be varied as desired. By mounting the rolls in wipingl contactwith the upper casing plate any tendency of the paste to follow therolls toward the charging end of the mill is easily overcome.

A further modification of a vertical type is illustrated in Fig. 3. Inthis figure the casing is-constructed with plane sides 11, with whichthe two sets of rolls, 1 and 1, are mounted in wiping contact and insuperposed series. Inasmuch as the attrition occurs in this case betweentwo moving surfaces, instead of between a moving and a stationarysurface as in the constructions previously described, it is desirablethat the two sets'of rolls should be driven at differing peripheralspeeds in order to intensify the rubbing action. For example, the rolls1 may be driven at about 15-20 revolutions per minute, and the rolls 1avat a somewhat higher rate, say 20-30 revolutions per minute, thesefigures being given however merely by way of example. In thisconstruction it is referred to provide above each set of ro @except theuppermostor feeding rolls a rid w ich may comprise a number vo sti ironrods 12, say three-eighths inch in diameterand lying parallel to eachother at two to three inch intervals, said rods extending between theside plates of removable iron frames 13, which 1n turn rest uponangle-bars or equivalent supports 14. The

purpose of these gridsv is to retain the paste" 1n the spacesintermediate the rolls for theof intense attrition may be necessary to.

aord time for a certain penetration of the defiocculating agent into thesubstance of the minute masses which are to be deflocculated, thesurface portions of these minute masses being rubbed ofor removed duringthe ensuing period ofattrition. Whatever the explanation maybe, the facthas been clearly demonstrated that the deflocculationproceeds mostrapidly when the operation is subdivided as described above into more orless definite and distinct periods of attrition and relative rest,irrespective ofthe means employed for accomplishing such subdivision ofthe operation.

A method of defiocculating solid ma# terials, consisting in subjectingsaid mal terials, mixed with a delocculating agent and in paste form, toalternate periods of attrition and relative rest, until the desiredpercentage of deflocculation is attained.

- In testimon whereof I affix my signature in presence o two witnesses.

EDWARD GOODRIGH ACHESON.

Witnesses:

LELIA M. TINSLEY, A. GoLDm GOLDMAN.

